The subject invention relates to bearings and more particularly to a diamond thrust bearing such as is employed for example in the downhole drilling art. The invention provides a bearing exhibiting significant improvement in load carrying capability and manufacturing efficiency.
In the prior art, thrust bearings are known which employ bearing inserts comprising hardmetal or carbide studs having planar, polycrystalline diamond faces. Bearings employing such inserts have provided a useful, but still limited, load carrying ability.
In manufacture, such diamond faced bearing inserts have been inserted into wells machined into associated bearing races and brazed into place. This procedure has the disadvantage that the wells must all be drilled to the same precise depth, in order to insure that the planar diamond bearing faces all lie in a common plane in the finished product.
Another drawback of the prior art approach is that replacement of worn or damaged bearing inserts is difficult. The structural member into which the bearing inserts are inserted may be very expensive. It may, for example, carry a radial bearing comprised of a tungsten carbide matrix. If the bearing inserts become worn, it may be impossible to replace them without destroying the utility of the associated structural member. Damage to the associated structural member may occur, for example, through structural deformation when heat is applied to loosen brazing material originally used to bond the bearing inserts into their associated recesses. Such damage may be particularly undesirable where the structure is a unitary bearing sleeve having diamond faced thrust bearings and a radial matrix bearing.